Model # 345372

Internet #202023037

GREAT STUFF 16 oz. Fireblock Insulating Foam Sealant

Discontinued GREAT STUFF

16 oz. Fireblock Insulating Foam Sealant

  • Save money and time by using this fire code approved formula
  • Air-sealing and insulating saves up to 20% on home energy costs
  • 16 oz. Fireblock Insulating Foam Sealant
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Product Overview

GREAT STUFF Fireblock Insulating Foam Sealant can save much more than energy costs. By sealing the pipe, cable and duct penetrations, you minimize airflow. During a fire, that means flames, harmful gasses and toxic smoke cannot spread as quickly. And in an emergency, that could make all the difference. The fact that it helps you conserve energy, reduce drafts and save on heating and cooling costs is great too.

  • Impedes spread of fire and smoke through service penetrations
  • Recognized as an alternate fireblocking material for residential construction; tested according to ASTM E84, ASTM E814 (Modified), UL 1715
  • Seals service penetrations between floors and electrical runs through wall studs
  • Airtight, water-resistant and has exceptional adhesion to building materials
  • Tack free in 6 minutes; trims in 30 minutes; cures rigid in 8 hours
  • Bright orange colored foam for easy code identification
  • All-direction dispensing

    GREAT STUFF insulating foam

  • How much do you need? Let our calculator help:
    Insulation calculator button

Info & Guides

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Product Depth (in.)
Product Height (in.)
Product Width (in.)


Insulation R-Value
Insulation Type
Spray Foam
Paintable / Stainable
Product Weight (oz.)
16 oz
Two Part

Warranty / Certifications

Fire Block Rated
Warranty Information

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Customer Questions & Answers

can Great Stuff Fireblock be used for filling gaps between cabinets and stove vents?

Asked by: Handylad
I would.
Answered by: scameron728
Date published: 2016-11-22

Is this product safe for use around non-metallic cable.

Can this foam be used around nonmetallic romex cable in a residental environment
Asked by: Cowman79
I'm not a chemical engineer nor am I a polymer scientist, but I've done exactly what you are considering and found that the foam cures and becomes inert the same day it is applied. I have no regrets after using it in this manner and will do so again whenever need arises.
Answered by: scameron728
Date published: 2016-11-15

What R-value does Great Stuff Fireblock (Model 345372) provide? Can it be used for insulating existing wall cavities?

Asked by: Anonymous
Yes the R-value is the same as the other cans of expanding foam and probably depends on the thickness you apply. But guess what?? This product has a combustion temperature of 240 degrees. ....way lower than actual wood does. Why use this when actual fiberglass insulation would work. Or just use regular expanding foam. Dont think because this can is labeled "fireblock" that it could actually resist a fire. They just hope you dont read the label.
Answered by: skycamper
Date published: 2016-08-08

Can I use this product to insulate my metal stud walls for an exterior Brick oven pizza?

Asked by: John
Dear John: I definitely hope you have NOT tried to insulate the walls around your brick pizza oven with the product. Although the label on the can says, "Fireblock", this version of Great Stuff is NOT approved as a "fireblock" product and will ignite at just 240 degrees F -- just like all versions of Great Stuff. It is a fire hazard and should not be used near any source of heat or flame. Home Depot sells other insulation products that are fireproof, with good insulation performance. The best option is Roxul rock wool, which you can stuff into the gaps between your brick oven and the metal stud walls. Roxul is much denser than fiberglass, mold kind of like clay and stays where you put it. The R value is 4 per inch, almost as good as flammable foam board. See: Roxul Comfortbatt Model # RXCB351525, Home Depot Internet # 202090820 Store SKU # 974419 Many Home Depot stores also carry Roxul ComfortBoard -- a 'board like' version that is similar to foamboard, but fireproof. See: Roxul Comfortboard Model # RXCB11224, Home Depot Internet # 206789748 Store SKU # 1001748089 I hope this is helpful. Mark
Answered by: BvilleBound
Date published: 2016-08-23
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Customer Reviews

16 oz. Fireblock Insulating Foam Sealant is rated 2.5 out of 5 by 8.
Rated 1 out of 5 by from Good Luck Getting it from the can! I am an avid user of the standard "Great Stuff" products from the large gaps, door and window Jambs, and the standard foam. I have had great success with all that I have used to this point trying to insulate around my home. Recently, I have taken on the task of re-wiring and re-insulating my attic. The process in inherently arduous and frustrating due to the nature of the project alone. I bought all new IC rated fixtures to be installed from the attic side of the drywall. The intention was to install the fixtures and foam seal around them with the Fireblock foam. I bought 8 cans. Out of the 8 cans, I was only able to successfully use 2. Right off 2 cans the straw nozzle broke when screwing them to the can. The other 4 cans the nozzle on the can broke off when trying to get the foam to dispense... This leaves 4 "useable cans" with 6 nozzles right? Wrong, 2 more nozzles broke off of 2 more of the cans when I was able to get good nozzles onto them. First I had to drive all across town visiting 4 department stores, and 2 home centers to find enough of the fireblock to complete my job, but then ended up with only 2 useable cans... Major disappointment.
Date published: 2012-08-07
Rated 3 out of 5 by from Works good for its designed usage The product information can be misleading if you are unfamiliar with the Building and Fire Code requirements for this type of material. This product is for RESIDENTIAL COMBUSTIBLE FIREBLOCK usage only. DO NOT use for penetrations of Commercial Fire Stop Systems where the Fire Barrier/Wall must be maintained to its designed rating. Polyurethane foam products ARE combustible even after "drying" into a solid foam and therefore can not be used as part of a required Commercial Fire Stop System. The appropriate Fire Seal or Fire Caulk should be used. Make absolutely sure you are using this product appropriately, DO NOT ASSUME.
Date published: 2012-05-10
Rated 1 out of 5 by from Messy & wasteful I used Pestblock to stop honeybees from getting between the siding and wall of house. The screw-on applicator quickly became clogged and the sticky foam came out in gobs that would not stay in place. Luckily I think there is enough in the one spot where the bees were entering that it might accomplish the job, but I am greatly unhappy with the product. The applicator straw, after having to use a coat hanger wire to clear the clogs, broke and the canister is more than 1/2 full of liquid, so you probably should make it in smaller containers and state on the label it is a one-use item. What a messy, wasteful product!!!!!!
Date published: 2013-09-01
Rated 2 out of 5 by from "One time use" not mentioned on packaging I had a very small job (blocking cracks and holes to deter mice) and bought a 12 oz can. It worked pretty much as-advertised ... EXCEPT: There is no way to clean the nozzle, and according to DOW on this website, DOW does not offer replacements for the "straw applicator". I'm sorry, but that's just plain deceptive. The can and packaging should have a PROMINENT "One Time Use" label. I have more cracks to fill -- I'll be looking for something else.
Date published: 2013-10-17
Rated 4 out of 5 by from this product is great Genaral question about all the Great Stuff Products can any of the products can be used around the ducking for exaust leading ouside from an eletric dryer? reason i ask is becouse i have a coold draft coming in. Thanks
Date published: 2014-01-18
Rated 1 out of 5 by from Ignites at 240F ... Totally misleading Not sure why they call it fireblock when it is highly flammable--both solid and in the can. Yes, it keeps air from feeding a fire but under flame it ignites immediately. Don't expect Dow or 3M to change the name... It's an industry standard nomenclature.
Date published: 2013-05-31
Rated 3 out of 5 by from Question for Dow Can this foam be used to fill the gaps around a hot radiator pipe? Hot steam goes through it. Thanks.
Date published: 2013-10-26
Rated 5 out of 5 by from fireblock I picked this product because this one I used the most this year,I have used all of them in my 128 year old home and I am please with all of your product.
Date published: 2012-03-29
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